Add a builtin FnPtr trait

compiler/rustc_const_eval/src/interpret/terminator.rs

@@ -382,6 +382,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             | ty::InstanceDef::FnPtrShim(..)
             | ty::InstanceDef::DropGlue(..)
             | ty::InstanceDef::CloneShim(..)
+            | ty::InstanceDef::FnPtrAddrShim(..)
             | ty::InstanceDef::Item(_) => {
                 // We need MIR for this fn
                 let Some((body, instance)) =